Effect of Heat Development Caused by High Speed Tensile Deformation on the Stress-Strain Curve of Polyester Filament Yarn.

The paper contains an account of a research into the effect on metals of different speeds of fracture, using a specially designed high-speed testing machine which is described in detail. The experiments were conducted both in this machine and in a 5-ton variable-speed autographic tensile machine, on five steels, the rate of loading being varied for each. With the high-speed machine toughness, ductility, time to produce fracture, and the stress-strain curve were obtained. The results of these combined tests, given in tables and graphs, show that there is a marked increase in stress due to higher speed of testing; and also that the work required to cause fracture increases with the speed. For mild steel the stress at the initial yield point was found to be in excess of that at the maximum point, when the speed of testing was increased the ductility did not appear to suffer.

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Mechanical Behavior of Materials under Tensile Loads

10.31399/asm.tb.tt2.t51060013 ◽

2004 ◽

pp. 13-31

Keyword(s):

Tensile Test ◽

Mechanical Behavior ◽

Tensile Deformation ◽

True Strain ◽

Strain Curve ◽

Tensile Specimen ◽

Stress Strain Curve ◽

Stress Strain ◽

Mathematical Expressions ◽

Reduction In Area

Abstract This chapter focuses on mechanical behavior under conditions of uniaxial tension during tensile testing. It begins with a discussion on the parameters that are used to describe the engineering stress-strain curve of a metal, namely, tensile strength, yield strength or yield point, percent elongation, and reduction in area. This is followed by a section describing the parameters determined from the true stress-true strain curve. The chapter then presents the mathematical expressions for the flow curve. Next, it reviews the effect of strain rate and temperature on the stress-strain curve. The chapter then describes the instability in tensile deformation and stress distribution at the neck in the tensile specimen. It discusses the processes involved in ductility measurement and notch tensile test in tensile specimens. The parameter that is commonly used to characterize the anisotropy of sheet metal is covered. Finally, the chapter covers the characterization of fractures in tensile test specimens.

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Constitutive Model of 30CrMoA Steel with Strain Correction

Metals ◽

10.3390/met10091214 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1214

Author(s):

Song Zhang ◽

Xuedao Shu ◽

Jitai Wang ◽

Yingxiang Xia

Keyword(s):

Flow Stress ◽

Constitutive Model ◽

High Speed ◽

Strain Curve ◽

Material Constant ◽

Test Machine ◽

Experimental Stress ◽

High Speed Train ◽

Stress Strain Curve ◽

Stress Strain

It is necessary to establish a constitutive model of 30CrMoA steel to optimize the forming shape and mechanical properties of high-speed train axles. The experimental stress–strain curve of 30CrMoA steel was obtained by an isothermal compression test on a Gleeble-3500 thermal simulation test machine under temperature of 1273~1423 K and strain rate of 0.01~10 s−1. Considering the effect of strain on the material constant, an empirical constitutive model was proposed with strain correction for 30CrMoA steel. In addition, the material constant in the constitutive model is determined by linear regression analysis of the experimental stress–strain curve. Comparing the theoretical value and experimental value of flow stress, the correlation R is 0.9828 and the average relative error (ARRE) is 4.652%. The constitutive model of 30CrMoA steel with strain correction can reasonably predict the flow stress under various conditions. The results provide an effective numerical tool for further study on accurate near-net forming of high-speed train axles.

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Modelling of the Strain Hardening Behaviour of Die-Cast Magnesium-Aluminium-Rare Earth Alloy

Advanced Engineering Forum ◽

10.4028/www.scientific.net/aef.35.1 ◽

2020 ◽

Vol 35 ◽

pp. 1-8

Author(s):

Hua Qian Ang

Keyword(s):

Strain Hardening ◽

Tensile Deformation ◽

Deformation Behaviour ◽

Strain Curve ◽

Deformation Mode ◽

Prismatic Slip ◽

Stress Strain Curve ◽

Stress Strain ◽

Die Cast ◽

Cast Magnesium

The tensile deformation behaviour of magnesium alloy AE44 (Mg-4Al-4RE) under strain rates ranging from 10-6 to 10-1 s-1 has been investigated. Present study shows that the deformation mode begins with the activation of elastic (Stage 1), followed by <a> basal slip and twinning (Stage 2), <a> prismatic slip (Stage 3) and finally to <c+a> pyramidal slip (Stage 4). The commencement of these deformation mechanisms results in four distinct stages of strain hardening in the stress-strain curve. In this work, the four stages of deformation behaviour are modelled, and an empirical equation is proposed to predict the entire stress-strain curve. Overall, the model predictions are in good agreement with the experimental data. This study on the decomposition of stress-strain curve into four stages provides insights into the contribution of individual deformation mechanism to the overall deformation behaviour and opens a new way to assess mechanical properties of die-cast magnesium alloys.

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Subultimate Prestrain and Aging in Mild Steel

Journal of Basic Engineering ◽

10.1115/1.3650547 ◽

1965 ◽

Vol 87 (2) ◽

pp. 319-324 ◽

Cited By ~ 2

Author(s):

D. K. Felbeck ◽

W. G. Gibbons ◽

W. G. Ovens

Keyword(s):

Mild Steel ◽

High Speed ◽

Strain Curve ◽

Local Stress ◽

Tensile Tests ◽

Stress Strain Curve ◽

Stress Strain ◽

Limited Region ◽

Small Increments ◽

Necessary And Sufficient

Room-temperature tensile straining of mild steel followed by aging at 350 F causes return of the upper yield and a raising of the stress-strain curve. Tensile tests on a special rimmed steel of low Mn/C ratio show not only the expected raising of the stress-strain curve, but raising by an additional amount when several small increments of strain are each followed by aging at moderate temperatures. Longitudinal tensile prestrain by rolling gives substantially the same results. Tests of specimens prestrained in a limited region by impact or in slow tension and aged indicate that embrittlement of the whole specimen may result. The combined theories of Griffith and Orowan, plus an extension of the Ludwik triaxiality concept, can provide a consistent description of the local stress and average stress (energy) criteria that are necessary and sufficient for high-speed low-energy fracture to occur.

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Ultra-Speed Tensile of Rubber and Synthetic Elastomers

Rubber Chemistry and Technology ◽

10.5254/1.3543031 ◽

1951 ◽

Vol 24 (1) ◽

pp. 144-160

Author(s):

D. S. Villars

Keyword(s):

Tensile Strength ◽

High Speed ◽

Relaxation Times ◽

Strain Curve ◽

Stress Strain Curve ◽

Stress Strain ◽

Elongation At Break ◽

Different Types ◽

Speed Up ◽

Pass Through

Abstract A high speed stress-strain machine has been developed which is capable of recording the stress-strain curve of elastomers at elongation rates up to 270 per cent/msec. Data are reported on two series of gum and tread stocks of Hevea and of the synthetic elastomers, GR-S, Hycar-OR, Butyl, Perbunan, and Neoprene-GN. The second (elastomer) series was also run at 150° C. In general, stress-strain curves fall into two classes. Stocks of elastomers which are known to crystallize on stretching tend to show tensile strengths which decrease with increasing speed up to about 10 per cent/msec, pass through a minimum, and rise more or less drastically to values 100 per cent (or more) greater than the Scott tensile strength. Elastomers which do not crystallize on stretching tend to show a steady rise in tensile strength with increasing speed. Elongation at break curves show a maximum with crystallizing stocks and no maximum with noncrystallizing stocks. The shape of the modulus vs. speed curves is accounted for on the hypothesis of different types of slipping bonds with different characteristic relaxation times. The shift of curves for tread stocks with temperature allows the estimation of a heat of activation of slippage. This comes out to be of the order of 3 kg.-cal.

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On the inhomogeneity of plastic deformation in the crystals of an aggregate

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1948.0035 ◽

1948 ◽

Vol 193 (1032) ◽

pp. 89-97 ◽

Cited By ~ 50

Keyword(s):

Plastic Deformation ◽

Grain Boundaries ◽

Single Crystals ◽

Tensile Deformation ◽

Strain Curve ◽

Stress Strain Curve ◽

Stress Strain ◽

X Ray

The variation of plastic deformation in aluminium specimens consisting of large crystals has been determined by measuring elongation and hardness at various points after tensile deformation. The deformation varied from grain to grain, and also within each grain the deformation near the boundary was greater or smaller than at the centre according to whether the neighbour was more or less deformed, i. e. there is not necessarily inhibition of slip near grain boundaries. These results were supported by metallographic and X-ray observations. Their importance with respect to the calculation of the stress-strain curve of aggregates from those of single crystals is discussed. It is suggested that a mechanism other than slip operates near the grain boundaries during deformation, and even within the crystals during large extensions.

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High speed tensile test of steel sheets for the stress-strain curve at the intermediate strain rate

International Journal of Automotive Technology ◽

10.1007/s12239-009-0023-3 ◽

2009 ◽

Vol 10 (2) ◽

pp. 195-204 ◽

Cited By ~ 105

Author(s):

H. Huh ◽

J. H. Lim ◽

S. H. Park

Keyword(s):

Tensile Test ◽

Strain Rate ◽

High Speed ◽

Strain Curve ◽

Intermediate Strain Rate ◽

Stress Strain Curve ◽

Stress Strain ◽

Steel Sheets

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Tensile Behavior of Foamed Aluminum with Closed-Cell

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.480-481.117 ◽

2011 ◽

Vol 480-481 ◽

pp. 117-119

Author(s):

Fang Wang ◽

Lu Cai Wang ◽

Jian Guo Wu

Keyword(s):

Deformation Process ◽

Tensile Deformation ◽

Strain Curve ◽

Tensile Behavior ◽

Deformation Mechanisms ◽

Compression Stress ◽

Plastic Yielding ◽

Stress Strain Curve ◽

Stress Strain ◽

Closed Cell

Foamed aluminum has been applied in many fields due mainly to its excellent properties. The tensile deformation process and characteristics of foamed aluminum with closed-cell were studied in this paper and the deformation mechanisms were discussed. The results show that foamed aluminum fractured without necking. The tensile stress-strain curves have similar characteristics, the linear elasticity at a low stresses followed by plastic yielding, strain hardening and rupture, which has obvious difference with compression stress-strain curve. The fracture mechanism is neither brittle fracture nor plastic fracture. The defects existed in foamed aluminum interior have important influence on tensile property.

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